Why does my toilet flush when I toss a bucket of water in it?

The water level in the bowl rises above the hidden siphon, so starts the siphon effect (which = flushing). You can use even less water if to pour from a good height, such that water is pushed up into the siphon. That’s how you flush a toilet with minimal water when there are problems with your water service. Loading 2–5 gallons of water into the reservoir when there are water problems is not the way to go.

I learned that while living in Thailand in the 70’s. Water was available only at night. We pumped into barrels for use during the day. Flushed our 5 gal toilet with only 1 gallon.

<———- is wondering why he’s throwing a bucket of water into his toilet. Boredom?

@smudges I was dumping the water from my air conditioner.

^^ Ohhh ok! That had me a little worried. LOL kidding

@RedDeerGuy1 – now you know to flush a toilet if water goes out but you still have power on a hot day.

When you flush, you’re releasing water into the bowl. It’s not really different to pouring water from a bucket.

There’s a u-bend, and a siphon (basically just a straight pipe) at the back of the u-bend. The water in the bowl will always go to the level of the siphon.

When you flush you are tossing in a bucket of water.

That’s how you empty the toilet to replace or repair it. Turn off the water supply, dump a big bucket of water in from a height (stand on a chair) and the water will mostly rush down the drain and won’t be replaced. Ta da!